Many more classes of beyond-planar graphs have been studied, see
[1]}, [2]}, [3]}, some of
which are relevant for this paper. A 1-planar drawing is
IC-planar [4]}, [5]}, [6]} if
each vertex is incident to at most one crossed edge. It is
fan-planar [7]}, [8]}, [9]}
if it is fan-crossing and excludes crossings of an edge from both
sides, called configuration II in [9]}, see
Fig. REF (c). Configuration II is a
restriction, since there are fan-crossing graphs that are
not fan-planar [11]}. However, it has no impact on the
density [11]} and the results on fan-planar graphs proved
in [13]}, [7]}, [8]}.
